TI1 DRV8884PWP 1a stepper motor driver Datasheet

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DRV8884
SLVSDA5A – JANUARY 2016 – REVISED MARCH 2016
DRV8884 1.0-A Stepper Motor Driver With Integrated Current Sense
1 Features
2 Applications
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PWM Microstepping Stepper Motor Driver
– Up to 1/16 Microstepping
– Non-Circular and Standard ½ Step Modes
Integrated Current Sense Functionality
– No Sense Resistors Required
– ±6.25% Full-Scale Current Accuracy
Slow and Mixed Decay Options
8.0- to 37-V Operating Supply Voltage Range
Low RDS(ON): 1.4 Ω HS + LS at 24 V, 25°C
High Current Capacity
– 1.0-A Full Scale per Bridge
– 0.7-A rms per Bridge
Fixed Off-Time PWM Chopping
Simple STEP/DIR Interface
Low-Current Sleep Mode (20 μA)
Small Package and Footprint
– 24 HTSSOP (PowerPAD™)
Protection Features
– VM Undervoltage Lockout (UVLO)
– Charge Pump Undervoltage (CPUV)
– Overcurrent Protection (OCP)
– Thermal Shutdown (TSD)
– Fault Condition Indication Pin (nFAULT)
Multi-Function Printers and Scanners
Laser Beam Printers
3D Printers
Automatic Teller and Money Handling Machines
Video Security Cameras
Office Automation Machines
Factory Automation and Robotics
3 Description
The DRV8884 device is a stepper motor driver for
industrial equipment applications. The device has two
N-channel power MOSFET H-bridge drivers, a
microstepping indexer, and integrated current sense.
The DRV8884 is capable of driving up to 1.0-A full
scale or 0.7-A rms output current (depending on
proper PCB ground plane for thermal dissipation and
at 24 V and TA = 25°C).
The DRV8884 integrated current sense functionality
eliminates the need for two external sense resistors.
The STEP/DIR pins provide a simple control
interface. The device can be configured in full-step up
to 1/16 step modes. A low-power sleep mode is
provided for very-low quiescent current standby using
a dedicated nSLEEP pin.
Internal protection functions are provided for
undervoltage, charge pump faults, overcurrent, short
circuits, and overtemperature. Fault conditions are
indicated by an nFAULT pin.
Device Information(1)
PART NUMBER
DRV8884
PACKAGE
HTSSOP (24)
BODY SIZE (NOM)
7.80 mm × 4.40 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
Simplified Schematic
Microstepping Current Waveform
8 to 37 V
Full-scale current
Step size
Stepper
Motor Driver
+
t
Output Current
M
1.0 A
t
Controller
RMS current
DRV8884
+
STEP/DIR
Decay mode
Current Sense
1/16 µstep
1.0 A
AOUT
BOUT
Step Input
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
DRV8884
SLVSDA5A – JANUARY 2016 – REVISED MARCH 2016
www.ti.com
Table of Contents
1
2
3
4
5
6
7
Features ..................................................................
Applications ...........................................................
Description .............................................................
Revision History.....................................................
Pin Configuration and Functions .........................
Specifications.........................................................
1
1
1
2
3
4
6.1
6.2
6.3
6.4
6.5
6.6
6.7
4
4
5
5
6
8
9
Absolute Maximum Ratings ......................................
ESD Ratings..............................................................
Recommended Operating Conditions.......................
Thermal Information ..................................................
Electrical Characteristics...........................................
Indexer Timing Requirements...................................
Typical Characteristics ..............................................
Detailed Description ............................................ 11
7.1 Overview ................................................................. 11
7.2 Functional Block Diagram ....................................... 12
7.3 Feature Description................................................. 13
7.4 Device Functional Modes........................................ 26
8
Application and Implementation ........................ 27
8.1 Application Information............................................ 27
8.2 Typical Application .................................................. 27
9
Power Supply Recommendations...................... 30
9.1 Bulk Capacitance ................................................... 30
10 Layout................................................................... 31
10.1 Layout Guidelines ................................................. 31
10.2 Layout Example .................................................... 31
11 Device and Documentation Support ................. 32
11.1
11.2
11.3
11.4
11.5
Documentation Support ........................................
Community Resources..........................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
32
32
32
32
32
12 Mechanical, Packaging, and Orderable
Information ........................................................... 32
4 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Original (January 2016) to Revision A
•
2
Page
Changed the device status from Product Preview to Production Data ................................................................................. 1
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DRV8884
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SLVSDA5A – JANUARY 2016 – REVISED MARCH 2016
5 Pin Configuration and Functions
PWP Package
24-Pin HTSSOP
Top View
1
24
2
23
Thermal Pad - GND
CPL
CPH
VCP
VM
AOUT1
PGND
AOUT2
BOUT2
PGND
BOUT1
VM
GND
3
4
5
6
7
8
9
10
22
21
20
19
18
17
16
15
11
14
12
13
DECAY
TRQ
M1
M0
DIR
STEP
ENABLE
nSLEEP
RREF
nFAULT
DVDD
AVDD
Pin Functions
PIN
NAME
PWP
CPL
1
CPH
2
VCP
3
VM
4
11
AOUT1
5
AOUT2
7
PGND
6
9
TYPE
DESCRIPTION
—
Charge pump output
Connect a 0.022-µF ceramic capacitor rated for VM from CPH to
CPL
O
Charge pump output
Connect a 16-V, 0.22-µF ceramic capacitor to VM
Power supply
Connect to motor supply voltage; bypass to GND with two 0.01-µF
capacitors (one for each pin) plus a bulk capacitor rated for VM
O
Winding A output
Connect to stepper motor winding
O
Power FET ground
Must be connected to ground
O
Winding B output
Connect to stepper motor winding
Device ground
Must be connected to ground
PWR
BOUT2
8
BOUT1
10
GND
12
PWR
AVDD
13
—
Internal regulator
Internal supply voltage; bypass to GND with a 6.3-V, 0.47-µF
ceramic capacitor
DVDD
14
—
Internal regulator
Internal supply voltage; bypass to GND with a 6.3-V, 0.47-µF
ceramic capacitor
nFAULT
15
O
Fault indication pin
Pulled logic low with fault condition; open-drain output requires an
external pullup
RREF
16
I
Current limit analog input
Connect resistor to ground to set full-scale chopping current
nSLEEP
17
I
Sleep mode input
Logic high to enable device; logic low to enter low-power sleep
mode; internal pulldown
ENABLE
18
I
Enable driver input
Logic high to enable device outputs and internal indexer; logic low to
disable; internal pulldown
STEP
19
I
Step input
A rising edge causes the indexer to advance one step; internal
pulldown
DIR
20
I
Direction input
Logic level sets the direction of stepping; internal pulldown
M0
21
M1
22
I
Microstepping mode
setting pins
Sets the step mode; tri-level pins.set the step mode; internal
pulldown
TRQ
23
I
Current scaling control pin Scales the output current; tri-level pin
DECAY
24
I
Decay mode setting pin
Copyright © 2016, Texas Instruments Incorporated
Sets the decay mode; see the Decay Modes section
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External Components
COMPONENT
PIN 1
PIN 2
CVM
VM
GND
Two 0.01-µF ceramic capacitors rated for VM
CVM
VM
GND
Bulk electrolytic capacitor rated for VM
CVCP
VCP
VM
16-V, 0.22-µF ceramic capacitor
CSW
CPH
CPL
0.022-µF X7R capacitor rated for VM
CAVDD
AVDD
GND
6.3-V, 0.47-µF ceramic capacitor
CDVDD
DVDD
GND
6.3-V, 0.47-µF ceramic capacitor
RnFAULT
VCC
RREF
(1)
RECOMMENDED
(1)
nFAULT
RREF
GND
>4.7 kΩ
Resistor to limit chopping current must be installed. See the Typical Application
section for value selection.
VCC is not a pin on the DRV8884, but a VCC supply voltage pullup is required for open-drain output nFAULT; nFAULT may be pulled
up to DVDD
6 Specifications
6.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted)
(1)
Power supply voltage (VM)
Power supply voltage ramp rate (VM)
MIN
MAX
UNIT
–0.3
40
V
0
2
V/µs
Charge pump voltage (VCP, CPH)
–0.3
VM + 7
V
Charge pump negative switching pin (CPL)
–0.3
VM
V
Internal regulator voltage (DVDD)
–0.3
3.8
V
0
1
mA
Internal regulator voltage (AVDD)
–0.3
5.7
V
Control pin voltage (STEP, DIR, ENABLE, nFAULT, M0, M1, DECAY, TRQ, nSLEEP)
–0.3
5.7
V
Internal regulator current output (DVDD)
Open drain output current (nFAULT)
0
10
mA
Current limit input pin voltage (RREF)
–0.3
6.0
V
Continuous phase node pin voltage (AOUT1, AOUT2, BOUT1, BOUT2)
–0.7
VM + 0.7
V
1.7
A
Operating junction temperature, TJ
–40
150
°C
Storage temperature, Tstg
–65
150
°C
Peak drive current (AOUT1, AOUT2, BOUT1, BOUT2)
(1)
Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended
Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
6.2 ESD Ratings
VALUE
V(ESD)
(1)
(2)
4
Electrostatic discharge
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001
(1)
Charged-device model (CDM), per JEDEC specification JESD22-C101
±2000
(2)
±500
UNIT
V
JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
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6.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)
MIN
MAX
UNIT
VM
Power supply voltage
8
37
VCC
Logic level input voltage
0
5.3
ƒPWM
Applied STEP signal (STEP)
0
100
(1)
kHz
IDVDD
DVDD external load current
0
1
(2)
mA
IFS
Motor full scale current
0
1.0
Irms
Motor rms current
0
0.7
A
TA
Operating ambient temperature
–40
125
°C
(1)
(2)
V
V
A
STEP input can operate up to 500 kHz, but system bandwidth is limited by the motor load
Power dissipation and thermal limits must be observed
6.4 Thermal Information
DRV8884
THERMAL METRIC
(1)
PWP (HTSSOP)
UNIT
24 PINS
RθJA
Junction-to-ambient thermal resistance
36.1
°C/W
RθJC(top)
Junction-to-case (top) thermal resistance
18.3
°C/W
RθJB
Junction-to-board thermal resistance
15.8
°C/W
ψJT
Junction-to-top characterization parameter
0.4
°C/W
ψJB
Junction-to-board characterization parameter
15.7
°C/W
RθJC(bot)
Junction-to-case (bottom) thermal resistance
1.1
°C/W
(1)
For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report, SPRA953.
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6.5 Electrical Characteristics
over operating free-air temperature range (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
POWER SUPPLIES (VM, DVDD, AVDD)
VVM
VM operating voltage
8
VM ≈ 8 to 35 V, ENABLE = 1,
nSLEEP = 1, No motor load
IVM
VM operating supply current
IVMQ
VM sleep mode supply current
tSLEEP
Sleep time
nSLEEP = 0 to sleep-mode
tWAKE
Wake-up time
tON
Turn-on time
VDVDD
Internal regulator voltage
0- to 1-mA external load
VAVDD
Internal regulator voltage
No external load
5
nSLEEP = 0; TA = 25°C
nSLEEP = 0; TA = 125°C
37
V
8
mA
20
(1)
40
μA
50
200
μs
nSLEEP = 1 to output transition
0.85
1.5
ms
VM > UVLO to output transition
0.85
1.5
ms
2.9
3.3
3.6
V
4.5
5.0
5.5
V
CHARGE PUMP (VCP, CPH, CPL)
VVCP
VCP operating voltage
VM > 8 V
VM + 5.5
V
LOGIC-LEVEL INPUTS (STEP, DIR, ENABLE, nSLEEP, M1)
VIL
Input logic low voltage
0
0.8
VIH
Input logic high voltage
1.6
5.3
VHYS
Input logic hysteresis
100
IIL
Input logic low current
VIN = 0 V
IIH
Input logic high current
VIN = 5.0 V
RPD
Pulldown resistance
To GND
tPD
Propagation delay
STEP to current change
V
V
mV
–1
1
100
100
μA
μA
kΩ
1.2
μs
0.65
V
TRI-LEVEL INPUT (M0, TRQ)
VIL
Tri-level input logic low voltage
VIZ
Tri-level input Hi-Z voltage
0
VIH
Tri-level input logic high
voltage
IIL
Tri-level input logic low current
VIN = 0 V
IIZ
Tri-level input Hi-Z current
VIN = 1.3 V
IIH
Tri-level input logic high
current
VIN = 5.0 V
RPD
Tri-level pulldown resistance
To GND
30
RPU
Tri-level pullup resistance
To DVDD
1.1
1.5
V
5.3
V
μA
–80
5
μA
155
μA
60
90
kΩ
18
32
50
kΩ
–5
QUAD-LEVEL INPUT (DECAY)
VI1
Quad-level input voltage 1
5% resistor 5 kΩ to GND
0.07
0.11
0.13
V
VI2
Quad-level input voltage 2
5% resistor 15 kΩ to GND
0.24
0.32
0.40
V
VI3
Quad-level input voltage 3
5% resistor 45 kΩ to GND
0.71
0.97
1.20
V
VI4
Quad-level input voltage 4
5% resistor 135 kΩ to GND
2.12
2.90
3.76
V
IO
Output current
To GND
14
22
30
μA
CONTROL OUTPUTS (nFAULT)
VOL
Output logic low voltage
IO = 1 mA, RPULLUP = 4.7 kΩ
IOH
Output logic high leakage
VO = 5.0 V, RPULLUP = 4.7 kΩ
(1)
6
–1
0.5
V
+1
μA
Not tested in production; limits are based on characterization data
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Electrical Characteristics (continued)
over operating free-air temperature range (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
MOTOR DRIVER OUTPUTS (AOUT1, AOUT2, BOUT1, BOUT2)
RDS(ON)
High-side FET on resistance
VM = 24 V, I = 1 A, TA = 25°C
716
798
mΩ
RDS(ON)
Low-side FET on resistance
VM = 24 V, I = 1 A, TA = 25°C
684
749
mΩ
tRISE
(2)
Output rise time
100
ns
tFALL
(2)
Output fall time
100
ns
Output dead time
200
(2)
tDEAD
Vd
(2)
Body diode forward voltage
IOUT = 0.5 A
ns
0.7
1.0
V
28.1
30
31.9
kAΩ
1.18
1.232
1.28
V
PWM CURRENT CONTROL (RREF)
ARREF
RREF transimpedance gain
VRREF
RREF voltage
tOFF
PWM off-time
CRREF
Equivalent capacitance on
RREF
tBLANK
ΔITRIP
PWM blanking time
Current trip accuracy
RREF = 18 to 132 kΩ
μs
20
10
IRREF = 1.0 A, 63% to 100% current
setting
1.5
IRREF = 1.0 A, 0% to 63% current
setting
1.0
pF
µs
IRREF = 1.0 A, 10% to 20% current
setting, 1% reference resistor
–25%
25%
IRREF = 1.0 A, 20% to 63% current
setting, 1% reference resistor
–12.5%
12.5%
IRREF = 1.0 A, 71% to 100% current
setting, 1% reference resistor
–6.25%
6.25%
PROTECTION CIRCUITS
VM falling; UVLO report
7.8
VM rising; UVLO recovery
8.0
VUVLO
VM UVLO
VUVLO,HYS
Undervoltage hysteresis
Rising to falling threshold
100
VCPUV
Charge pump undervoltage
VCP falling; CPUV report
VM + 2.0
IOCP
Overcurrent protection trip
level
Current through any FET
tOCP
Overcurrent deglitch time
tRETRY
Overcurrent retry time
TTSD
Die temperature TJ
THYS
(2)
Thermal shutdown hysteresis
Die temperature TJ
(2)
V
A
1.9
1
Thermal shutdown
temperature
mV
1.7
1.3
(2)
V
2.8
μs
1.6
ms
150
°C
20
°C
Not tested in production; limits are based on characterization data
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6.6 Indexer Timing Requirements
TA = 25°C, over recommended operating conditions unless otherwise noted
NO.
(1)
MIN
MAX
UNIT
1
ƒSTEP
Step frequency
2
tWH(STEP)
Pulse duration, STEP high
970
ns
3
tWL(STEP)
Pulse duration, STEP low
970
ns
4
tSU(DIR, Mx)
Setup time, DIR or USMx to STEP rising
200
ns
5
tH(DIR,
Hold time, DIR or USMx to STEP rising
200
ns
Mx)
500
(1)
kHz
STEP input can operate up to 500 kHz, but system bandwidth is limited by the motor load
1
2
3
STEP
DIR, Mx
4
5
Figure 1. Timing Diagram
8
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6.7 Typical Characteristics
Over recommended operating conditions (unless otherwise noted)
6.4
6.2
6
S u p p ly C u r r e n t I V M ( m A )
S u p p ly C u r r e n t I V M ( m A )
6.2
6
5.8
T A = 125°C
T A = 85°C
5.6
T A = 25°C
T A = -40°C
5.4
5.6
5.4
5.2
5.2
5
5
5
10
15
20
25
30
35
Supply Voltage VM (V)
40
-40
-20
0
20
40
60
Ambient Temperature T
D001
Figure 2. Supply Current over VM
80
A
100
120
(qC)
140
D002
Figure 3. Supply Current over Temperature (VM = 24 V)
16
20
T A = 125°C
15
T A = 85°C
18
T A = 25°C
14
T A = -40°C
16
S le e p C u r r e n t I V M Q ( P A )
S le e p C u r r e n t I V M Q ( P A )
5.8
14
12
10
8
13
12
11
10
9
8
6
7
4
6
5
10
15
20
25
30
35
Supply Voltage VM (V)
40
-40
0
20
40
60
Ambient Temperature T
Figure 4. Sleep Current over VM
80
A
100
120
(qC)
140
D004
Figure 5. Sleep Current over Temperature (VM = 24 V)
1050
1050
TA = +125°C
TA = +85°C
TA = +25°C
TA = -40°C
950
900
1000
950
High-Side RDS(ON) (m:)
1000
High-Side RDS(ON) (m:)
-20
D003
850
800
750
700
650
600
900
850
800
750
700
650
600
550
550
500
500
-40
5
10
15
20
25
30
Supply Voltage VM (V)
35
Figure 6. High-Side RDS(ON) over VM
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40
D005
-20
0
20
40
60
80
100
Ambient Temperature TA (qC)
120
140
D006
Figure 7. High-Side RDS(ON) over Temperature (VM = 24 V)
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Typical Characteristics (continued)
Over recommended operating conditions (unless otherwise noted)
1000
950
TA = +125°C
TA = +85°C
TA = +25°C
TA = -40°C
Low-Side RDS(ON) (m:)
900
900
Low-Side RDS(ON) (m:)
950
850
800
750
700
650
850
800
750
700
650
600
600
550
550
500
5
10
15
20
25
30
Supply Voltage VM (V)
35
500
-40
40
-20
0
D007
Figure 8. Low-Side RDS(ON) over VM
20
40
60
80
100
Ambient Temperature T A (qC)
D008
2
TRQ = 0
TRQ = Z
TRQ = 1
3.336
1
0.7
0.5
3.333
3.33
3.327
3.324
IFS (A)
D V D D V o lta g e ( V )
140
Figure 9. Low-Side RDS(ON) over Temperature (VM = 24 V)
3.339
3.321
3.318
3.315
T A = 125°C
3.312
T A = 85°C
T A = 25°C
3.309
3.303
0
0.1
0.2
0.3
0.4
0.5
0.6
DVDD Load (mA)
0.7
0.8
0.9
1
D009
Figure 10. DVDD Regulator over Load (VM = 24 V)
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0.3
0.2
0.1
0.07
0.05
0.03
0.02
T A = -40°C
3.306
10
120
0.01
10
20
30
40 50 60 70
RREF (k:)
100
200
300
D010
Figure 11. Full-Scale Current over RREF Selection
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7 Detailed Description
7.1 Overview
The DRV8884 is an integrated motor driver solution for bipolar stepper motors. The device integrates two NMOS
H-bridges, integrated current sense and regulation circuitry, and a microstepping indexer. The DRV8884 can be
powered with a supply voltage between 8 and 37 V, and is capable of providing an output current with up to 1.7A peak, 1.0-A full-scale, or 0.7-A rms. Actual full-scale and rms current depends on ambient temperature, supply
voltage, and PCB ground plane size.
The DRV8884 integrates current sense functionality, which eliminates the need for high-power external sense
resistors. This integration does not dissipate the external sense resistor power, because the current sense
functionality is not implemented using a resistor-based architecture. This functionality helps improve component
cost, board size, PCB layout, and system power consumption.
A simple STEP/DIR interface allows easy interfacing to the controller circuit. The internal indexer is able to
execute high-accuracy microstepping without requiring the processor to control the current level. The indexer is
capable of full step and half step as well as microstepping to 1/4, 1/8, and 1/16. In addition to the standard halfstepping mode, a non-circular 1/2-stepping mode is available for increased torque output at higher motor rpm.
The current regulation is configurable with several decay modes of operation. The decay mode can be selected
as a fixed slow, slow/mixed, or mixed decay. The slow/mixed decay mode uses slow decay on increasing steps
and mixed decay on decreasing steps.
An adaptive blanking time feature automatically scales the minimum drive time with output current. This helps
alleviate zero-crossing distortion by limiting the drive time at low-current steps.
A torque DAC feature allows the controller to scale the output current without needing to scale the reference
resistor. The torque DAC is accessed using a digital input pin. This allows the controller to save power by
decreasing the current consumption when not high current is not required.
A low-power sleep mode is included that allows the system to save power when not driving the motor.
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7.2 Functional Block Diagram
VM
+
0.01 µF
VM
VM
0.01 µF
bulk
VM
Gate Drive
Off-time PWM
DVDD
1 mA
3.3-V LDO
STEP
DIR
Core Logic
ENABLE
nSLEEP
DVDD
Control
Inputs
M[1:0]
DVDD
DECAY
DVDD
TRQ
DVDD
IREF
RREF
Analog
Input
RREF
Protection
Output
nFAULT
Microstepping Indexer up to 1/16
0.47 µF
Gate Drive
0.47 µF
12
AOUT2
4
+
-
AIREF
PGND
SINE DAC
AIREF
VM
BOUT1
BIREF
VM
Undervoltage
GND
-
IREF
Overcurrent
Thermal
Step
Motor
VM
Gate Drive
5.0-V LDO
Off-time PWM
AVDD
+
AIREF
Gate Drive
CPL
AOUT1
BOUT2
+
-
0.022 µF
Charge
Pump
+
-
CPH
+
-
VCP
VM
Adaptive
Blanking
+
-
0.22 µF
Power
BIREF
PGND
IREF
4
SINE DAC
BIREF
PPAD
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7.3 Feature Description
7.3.1 Stepper Motor Driver Current Ratings
Stepper motor drivers can be classified using three different numbers to describe the output current: peak, rms,
and full-scale.
7.3.1.1 Peak Current Rating
The peak current in a stepper driver is limited by the overcurrent protection trip threshold, IOCP. The peak current
describes any transient duration current pulse, for example when charging capacitance, when the overall duty
cycle is very low. In general, the minimum value of IOCP specifies the peak current rating of the stepper motor
driver. For the DRV8884, the peak current rating is 1.7 A per bridge.
7.3.1.2 RMS Current Rating
The rms (average) current is determined by the thermal considerations of the IC. The rms current is calculated
based on the RDS(ON), rise and fall time, PWM frequency, device quiescent current, and package thermal
performance in a typical system at 25°C. The real operating rms current may be higher or lower depending on
heatsinking and ambient temperature. For the DRV8884, the rms current rating is 0.7 A per bridge.
7.3.1.3 Full-Scale Current Rating
The full-scale current describes the top of the sinusoid current waveform while microstepping. Because the
sinusoid amplitude is related to the rms current, the full-scale current is also determined by the thermal
considerations of the IC. The full-scale current rating is approximately √2 × Irms. The full-scale current is set by
VREF, the sense resistor, and torque DAC when configuring the DRV8884 (see Current Regulation for details).
For the DRV8884, the full-scale current rating is 1.0 A per bridge.
Full-scale current
Output Current
RMS current
AOUT
BOUT
Step Input
Figure 12. Full-Scale and rms Current
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Feature Description (continued)
7.3.2 PWM Motor Drivers
The DRV8884 contains drivers for two full H-bridges. Figure 13 shows a block diagram of the circuitry.
VM
AOUT1
Gate
Drive
AIREF
+
±
PWM Logic
+
Step
Motor
VM
Device Logic
±
AOUT2
Gate
Drive
+
±
AIREF
+
±
PGND
Figure 13. PWM Motor Driver Block Diagram
7.3.3 Microstepping Indexer
Built-in indexer logic in the DRV8884 allows a number of different stepping configurations. The Mx pins are used
to configure the stepping format as shown in Table 1.
Table 1. Microstepping Settings
M1
M0
STEP MODE
0
0
Full step (2-phase excitation) with 71% current
0
1
1/16 step
1
0
1/2 step
1
1
1/4 step
0
Z
1/8 step
1
Z
Non-circular 1/2 step
Table 2 shows the relative current and step directions for full-step through 1/16-step operation. The AOUT
current is the sine of the electrical angle; BOUT current is the cosine of the electrical angle. Positive current is
defined as current flowing from xOUT1 to xOUT2 while driving.
At each rising edge of the STEP input the indexer travels to the next state in the table (see Table 2). The
direction is shown with the DIR pin logic high. If the DIR pin is logic low, the sequence is reversed.
On power-up or when exiting sleep mode, keep the STEP pin logic low, otherwise the indexer will advance one
step.
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Note that if the step mode is changed from full, 1/2, 1/4, 1/8, or 1/16 to full, 1/2, 1/4, 1/8, or 1/16 while stepping,
the indexer will advance to the next valid state for the new MODE setting at the rising edge of STEP. If the step
mode is changed from or to non-circular 1/2 step, the indexer will immediately go to the valid state for that mode.
The home state is an electrical angle of 45°. This state is entered after power-up, after exiting logic undervoltage
lockout (UVLO), or after exiting sleep mode. Table 2 shows this state with the cells outlined in red.
Table 2. Microstepping Relative Current per Step (DIR = 1)
FULL STEP
1/2 STEP
1/4 STEP
1/8 STEP
1/16 STEP
ELECTRICAL
ANGLE
(DEGREES)
1
1
1
1
2
2
2
3
4
1
2
3
5
6
4
7
8
3
5
9
10
6
11
12
2
4
7
13
14
8
15
16
5
9
17
18
10
19
20
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AOUT
CURRENT (%
FULL-SCALE)
BOUT
CURRENT (%
FULL-SCALE)
0.000°
0%
100%
5.625°
10%
100%
3
11.250°
20%
98%
4
16.875°
29%
96%
5
22.500°
38%
92%
6
28.125°
47%
88%
7
33.750°
56%
83%
8
39.375°
63%
77%
9
45.000°
71%
71%
10
50.625°
77%
63%
11
56.250°
83%
56%
12
61.875°
88%
47%
13
67.500°
92%
38%
14
73.125°
96%
29%
15
78.750°
98%
20%
16
84.375°
100%
10%
17
90.000°
100%
0%
18
95.625°
100%
–10%
19
101.250°
98%
–20%
20
106.875°
96%
–29%
21
112.500°
92%
–38%
22
118.125°
88%
–47%
23
123.750°
83%
–56%
24
129.375°
77%
–63%
25
135.000°
71%
–71%
26
140.625°
63%
–77%
27
146.250°
56%
–83%
28
151.875°
47%
–88%
29
157.500°
38%
–92%
30
163.125°
29%
–96%
31
168.750°
20%
–98%
32
174.375°
10%
–100%
33
180.000°
0%
–100%
34
185.625°
–10%
–100%
35
191.250°
–20%
–98%
36
196.875°
–29%
–96%
37
202.500°
–38%
–92%
38
208.125°
–47%
–88%
39
213.750°
–56%
–83%
40
219.375°
–63%
–77%
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Table 2. Microstepping Relative Current per Step (DIR = 1) (continued)
FULL STEP
1/2 STEP
1/4 STEP
1/8 STEP
1/16 STEP
ELECTRICAL
ANGLE
(DEGREES)
AOUT
CURRENT (%
FULL-SCALE)
BOUT
CURRENT (%
FULL-SCALE)
3
6
11
21
41
225.000°
–71%
–71%
42
230.625°
–77%
–63%
43
236.250°
–83%
–56%
44
241.875°
–88%
–47%
45
247.500°
–92%
–38%
46
253.125°
–96%
–29%
47
258.750°
–98%
–20%
48
264.375°
–100%
–10%
49
270.000°
–100%
0%
50
275.625°
–100%
10%
51
281.250°
–98%
20%
52
286.875°
–96%
29%
53
292.500°
–92%
38%
54
298.125°
–88%
47%
55
303.750°
–83%
56%
56
309.375°
–77%
63%
57
315.000°
–71%
71%
58
320.625°
–63%
77%
59
326.250°
–56%
83%
60
331.875°
–47%
88%
61
337.500°
–38%
92%
62
343.125°
–29%
96%
63
348.750°
–20%
98%
64
354.375°
–10%
100%
1
360.000°
0%
100%
22
12
23
24
7
13
25
26
14
27
28
4
8
15
29
30
16
31
32
1
1
1
Non-circular 1/2–step operation is shown in Table 3. This stepping mode consumes more power than circular
1/2-step operation, but provides a higher torque at high motor rpm.
Table 3. Non-Circular 1/2-Stepping Current
NON-CIRCULAR 1/2 STEP
16
AOUT CURRENT
(% FULL-SCALE)
BOUT CURRENT
(% FULL-SCALE)
1
0
100
0
2
100
100
45
3
100
0
90
4
100
–100
135
5
0
–100
180
6
–100
–100
225
7
–100
0
270
8
–100
100
315
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ELECTRICAL ANGLE (°)
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7.3.4 Current Regulation
The current through the motor windings is regulated by an adjustable fixed-off-time PWM current regulation
circuit. When an H-bridge is enabled, current rises through the winding at a rate dependent on the DC voltage,
inductance of the winding, and the magnitude of the back EMF present. After the current hits the current
chopping threshold, the bridge enters a decay mode for a fixed 20-μs period of time to decrease the current.
After the off time expires, the bridge is re-enabled, starting another PWM cycle.
Motor Current (A)
ITRIP
tBLANK
tDRIVE
tOFF
Figure 14. Current Chopping Waveform
The PWM chopping current is set by a comparator which looks at the voltage across current sense FETs in
parallel with the low-side drivers. The current sense FETs are biased with a reference current that is the output of
a current-mode sine-weighted DAC whose full-scale reference current is set by the current through the RREF
pin. An external resistor is placed from the RREF pin to GND in order to set the reference current. In addition,
the TRQ pin can further scale the reference current.
The chopping current is calculated as shown in Equation 1.
ARREF (kA:)
30 (kA:)
IFS (A)
u TRQ (%)
u TRQ (%)
RREF (k :)
RREF (k:)
(1)
Example: If a 30-kΩ resistor is connected to the RREF pin, the chopping current will be 1 A (TRQ at 100%).
The TRQ pin is the input to a DAC used to scale the output current. The current scalar value for different inputs
is shown in Table 4.
Table 4. Torque DAC Settings
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TRQ
CURRENT SCALAR (TRQ)
0
100%
Z
75%
1
50%
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7.3.5 Controlling RREF With an MCU DAC
In some cases, the full-scale output current may need to be changed on the fly between many different values,
depending on motor speed and loading. The RREF pin reference current can be adjusted in system by tying the
RREF resistor to a DAC output instead of GND.
In this mode of operation, as the DAC voltage increases, the reference current will decrease, and therefore, the
full-scale current will decrease as well. For proper operation, the output of the DAC should not rise above VRREF.
MCU
DVDD
Analog
Input
IREF
RREF
RREF
DAC
Figure 15. Controlling RREF With a DAC
The chopping current as controlled by a DAC is calculated as in Equation 2.
IFS (A)
$RREF N$: u > 9RREF 9 ± 9DAC 9
VRREF (V) u RREF (k :)
@ u TRQ (%)
(2)
Example: If a 30-kΩ resistor is connected from the RREF pin to the DAC, and the DAC is outputting 0.5 V, the
chopping current will be 600 mA (TRQ at 100%).
7.3.6 Decay Modes
The DRV8884 decay mode is selected by setting the quad-level DECAY pin to the voltage range in Table 5.
Table 5. Decay Mode Settings
DECAY
18
INCREASING STEPS
DECREASING STEPS
100 mV
Can be tied to ground
Slow decay
Mixed decay: 30% fast
300 mV, 15 kΩ to GND
Mixed decay: 30% fast
Mixed decay: 30% fast
1.0 V, 45 kΩ to GND
Mixed decay: 60% fast
Mixed decay: 60% fast
2.9 V
Can be tied to DVDD
Slow decay
Slow decay
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AOUT Current
Increasing and decreasing current are defined in Figure 16. For the slow/mixed decay mode, the decay mode is
set as slow during increasing current steps and mixed decay during decreasing current steps. In full-step mode,
the decreasing steps decay mode is always used.
Increasing
Decreasing
Increasing
Decreasing
STEP Input
BOUT Current
AOUT Current
Decreasing
Increasing
Increasing
Decreasing
STEP Input
Figure 16. Definition of Increasing and Decreasing Steps
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Increasing Phase Current (A)
7.3.6.1 Mode 1: Slow Decay for Increasing and Decreasing Current
ITRIP
tBLANK
tOFF
tBLANK
Decreasing Phase Current (A)
tOFF
tDRIVE
tDRIVE
ITRIP
tBLANK
tOFF
tDRIVE
tBLANK
tDRIVE
tOFF
tBLANK
tDRIVE
Figure 17. Slow/Slow Decay Mode
During slow decay, both of the low-side FETs of the H-bridge are turned on, allowing the current to be
recirculated.
Slow decay exhibits the least current ripple of the decay modes for a given tOFF. However, on decreasing current
steps, slow decay takes a long time to settle to the new ITRIP level because the current decreases very slowly.
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Increasing Phase Current (A)
7.3.6.2 Mode 2: Slow Decay for Increasing Current, Mixed Decay for Decreasing Current
ITRIP
tBLANK
tOFF
tBLANK
Decreasing Phase Current (A)
tOFF
tDRIVE
tDRIVE
tBLANK
tDRIVE
ITRIP
tBLANK
tDRIVE
tFAST
tBLANK
tOFF
tDRIVE
tFAST
tOFF
Figure 18. Slow/Mixed Decay Mode
Mixed decay begins as fast decay for a time, followed by slow decay for the remainder of tOFF. In this mode,
mixed decay only occurs during decreasing current. Slow decay is used for increasing current.
This mode exhibits the same current ripple as slow decay for increasing current, since for increasing current, only
slow decay is used. For decreasing current, the ripple is larger than slow decay, but smaller than fast decay. On
decreasing current steps, mixed decay settles to the new ITRIP level faster than slow decay.
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7.3.6.3 Mode 3: Mixed Decay for Increasing and Decreasing Current
Increasing Phase Current (A)
ITRIP
tOFF
tBLANK
Decreasing Phase Current (A)
tOFF
tDRIVE
tDRIVE
tBLANK
tDRIVE
ITRIP
tBLANK
tDRIVE
tFAST
tBLANK
tOFF
tDRIVE
tFAST
tOFF
Figure 19. Mixed/Mixed Decay Mode
Mixed decay begins as fast decay for a time, followed by slow decay for the remainder of tOFF. In this mode,
mixed decay occurs for both increasing and decreasing current steps.
This mode exhibits ripple larger than slow decay, but smaller than fast decay. On decreasing current steps,
mixed decay settles to the new ITRIP level faster than slow decay.
In cases where current is held for a long time (no input in the STEP pin) or at very low stepping speeds, slow
decay may not properly regulate current because no back-EMF is present across the motor windings. In this
state, motor current can rise very quickly, and requires an excessively large off-time. Increasing/decreasing
mixed decay mode allows the current level to stay in regulation when no back-EMF is present across the motor
windings.
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7.3.7 Blanking Time
After the current is enabled in an H-bridge, the current sense comparator is ignored for a period of time (tBLANK)
before enabling the current sense circuitry. Note that the blanking time also sets the minimum drive time of the
PWM. Table 6 shows the blanking time based on the sine table index and the torque DAC setting. Note that the
torque DAC index is not the same as one step as given in Table 2.
Table 6. Adaptive Blanking
Time over Torque DAC and
Microsteps
tblank = 1.5 µs
SINE INDEX
tblank = 1.0 µs
TORQUE DAC (TRQ)
100%
75%
50%
16
100%
75%
50%
15
98%
73.5
49%
14
96%
72%
48%
13
92%
69%
46%
12
88%
66%
44%
11
83%
62.3%
41.5%
10
77%
57.8%
38.5%
9
71%
53.3%
35.5%
8
63%
47.3%
31.5%
7
56%
42%
28%
6
47%
35.3
23.5%
5
38%
28.5
19%
4
29%
21.8%
14.5%
3
20%
15%
10%
2
10%
7.5%
5%
1
0%
0%
0%
7.3.8 Charge Pump
A charge pump is integrated in order to supply a high-side NMOS gate drive voltage. The charge pump requires
a capacitor between the VM and VCP pins. Additionally, a low-ESR ceramic capacitor is required between pins
CPH and CPL.
VM
0.22 µF
VCP
VM
CPH
0.022 µF
VM
CPL
Charge
Pump
Figure 20. Charge Pump Diagram
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7.3.9 LDO Voltage Regulator
An LDO regulator is integrated into the DRV8884. DVDD can be used to provide a reference voltage. For proper
operation, bypass DVDD to GND using a ceramic capacitor.
The DVDD output is nominally 3.3 V. When the DVDD LDO current load exceeds 1 mA, the output voltage drops
significantly.
The AVDD pin also requires a bypass capacitor to GND. This LDO is for DRV8884 internal use only.
VM
+
AVDD
-
0.47 µF
VM
+
3.3 V
DVDD
-
0.47 µF
1 mA
max
Figure 21. LDO Diagram
If a digital input needs to be tied permanently high (that is, Mx, DECAY, or TRQ), it is preferable to tie the input
to DVDD instead of an external regulator. This saves power when VM is not applied or in sleep mode; DVDD is
disabled and current will not be flowing through the input pulldown resistors. For reference, logic level inputs
have a typical pulldown of 100 kΩ, and tri-level inputs have a typical pulldown of 60 kΩ.
7.3.10 Logic and Multi-Level Pin Diagrams
Figure 22 gives the input structure for logic-level pins STEP, DIR, ENABLE, nSLEEP, and M1.
DVDD
100 kŸ
Figure 22. Logic-level Input Pin Diagram
Tri-level logic pins M0 and TRQ have the following structure shown in Figure 23.
DVDD
+
DVDD
-
32kŸ
DVDD
60kŸ
+
-
Figure 23. Tri-level Input Pin Diagram
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Quad-level logic pin DECAY has the following structure shown in Figure 24.
DVDD
+
DVDD
20µA
DVDD
+
DVDD
+
-
Figure 24. Quad-level Input Pin Diagram
7.3.11 Protection Circuits
The DRV8884 is fully protected against undervoltage, charge pump undervoltage, overcurrent, and
overtemperature events.
7.3.11.1 VM UVLO
If at any time the voltage on the VM pin falls below the VM UVLO threshold voltage (VUVLO), all FETs in the Hbridge will be disabled, the charge pump will be disabled, the logic will be reset, the DVDD regulator is disabled,
and the nFAULT pin will be driven low. Operation resumes when VM rises above the UVLO threshold. The
nFAULT pin is released after operation has resumed. Decreasing VM below this undervoltage threshold will reset
the indexer position.
7.3.11.2 VCP Undervoltage Lockout (CPUV)
If at any time the voltage on the VCP pin falls below the charge pump UVLO threshold voltage, all FETs in the Hbridge will be disabled and the nFAULT pin will be driven low. Operation resumes when VCP rises above the
CPUV threshold. The nFAULT pin is released after operation has resumed.
7.3.11.3 Overcurrent Protection (OCP)
An analog current limit circuit on each FET limits the current through the FET by removing the gate drive. If this
analog current limit persists for longer than tOCP, all FETs in the H-bridge will be disabled and nFAULT will be
driven low.
The driver is re-enabled after the OCP retry period (tRETRY) has passed. nFAULT becomes high again after the
retry time. If the fault condition is still present, the cycle repeats. If the fault is no longer present, normal operation
resumes and nFAULT remains deasserted.
7.3.11.4 Thermal Shutdown (TSD)
If the die temperature exceeds safe limits, all FETs in the H-bridge will be disabled and the nFAULT pin will be
driven low. After the die temperature has fallen to a safe level, operation automatically resumes. The nFAULT pin
is released after operation has resumed.
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Table 7. Fault Condition Summary
FAULT
CONDITION
ERROR
REPORT
H-BRIDGE
CHARGE
PUMP
INDEXER
DVDD
RECOVERY
VM undervoltage
(UVLO)
VM < VUVLO
(max 7.8 V)
nFAULT
Disabled
Disabled
Disabled
Disabled
VM > VUVLO
(max 8.0 V)
VCP undervoltage
(CPUV)
VCP < VCPUV
(typ VM + 2.0 V)
nFAULT
Disabled
Operating
Operating
Operating
VCP > VCPUV
(typ VM + 2.7 V)
Overcurrent (OCP)
IOUT > IOCP
(min 1.7 A)
nFAULT
Disabled
Operating
Operating
Operating
tRETRY
Thermal Shutdown
(TSD)
TJ > TTSD
(min 150°C)
nFAULT
Disabled
Operating
Operating
Operating
TJ < TTSD – THYS
(THYS typ 20°C)
7.4 Device Functional Modes
The DRV8884 is active unless the nSLEEP pin is brought logic low. In sleep mode, the charge pump is disabled,
the H-bridge FETs are disabled Hi-Z, and the V3P3 regulator is disabled. Note that tSLEEP must elapse after a
falling edge on the nSLEEP pin before the device is in sleep mode. The DRV8884 is brought out of sleep mode
automatically if nSLEEP is brought logic high. Note that tWAKE must elapse before the outputs change state after
wake-up.
TI recommends to keep the STEP pin logic low when coming out of nSLEEP or when applying power.
If the ENABLE pin is brought logic low, the H-bridge outputs are disabled, but the internal logic will still be active.
A rising edge on STEP will advance the indexer, but the outputs will not change state until ENABLE is
deasserted.
Table 8. Functional Modes Summary
CONDITION
H-BRIDGE
CHARGE PUMP
INDEXER
V3P3
Operating
8 V < VM < 40 V
nSLEEP pin = 1
ENABLE pin = 1
Operating
Operating
Operating
Operating
Disabled
8 V < VM < 40 V
nSLEEP pin = 1
ENABLE pin = 0
Disabled
Operating
Operating
Operating
Sleep mode
8 V < VM < 40
nSLEEP pin = 0
Disabled
Disabled
Disabled
Disabled
VM undervoltage (UVLO)
Disabled
Disabled
Disabled
Disabled
VCP undervoltage (CPUV)
Disabled
Operating
Operating
Operating
Overcurrent (OCP)
Disabled
Operating
Operating
Operating
Thermal shutdown (TSD)
Disabled
Operating
Operating
Operating
Fault encountered
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8 Application and Implementation
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
8.1 Application Information
The DRV8884 is used in bipolar stepper control.
8.2 Typical Application
The following design procedure can be used to configure the DRV8884.
22
21
20
19
18
17
16
15
14
30 kŸ
13
0.47 µF
DECAY
CPL
TRQ
CPH
M1
VCP
M0
VM
DIR
STEP
AOUT1
PGND
ENABLE
AOUT2
nSLEEP
BOUT2
RREF
nFAULT
PGND
BOUT1
DVDD
VM
AVDD
GND
1
2
3
0.022 µF
0.22 µF
4
VM
5
0.01 µF
6
+
23
DRV8884PWP
7
±
24
8
9
Step
Motor
+
±
10
11
VM
12
0.01 µF
+
100 µF
0.47 µF
Figure 25. Typical Application Schematic
8.2.1 Design Requirements
Table 9 gives design input parameters for system design.
Table 9. Design Parameters
REFERENCE
EXAMPLE VALUE
Supply voltage
DESIGN PARAMETER
VM
24 V
Motor winding resistance
RL
2.6 Ω/phase
Motor winding inductance
LL
1.4 mH/phase
θstep
1.8°/step
nm
1/8 step
v
120 rpm
IFS
1.0 A
Motor full step angle
Target microstepping level
Target motor speed
Target full-scale current
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8.2.2 Detailed Design Procedure
8.2.2.1 Stepper Motor Speed
The first step in configuring the DRV8884 requires the desired motor speed and microstepping level. If the target
application requires a constant speed, then a square wave with frequency ƒstep must be applied to the STEP pin.
If the target motor speed is too high, the motor will not spin. Make sure that the motor can support the target
speed.
For a desired motor speed (v), microstepping level (nm), and motor full step angle (θstep),
v (rpm) u 360 (q / rot)
¦step VWHSV V
Tstep (q / step) u nm (steps / microstep) u 60 (s / min)
(3)
θstep can be found in the stepper motor data sheet, or written on the motor itself.
For the DRV8884, the microstepping level is set by the Mx pins and can be any of the settings in Table 10.
Higher microstepping will mean a smother motor motion and less audible noise, but will increase switching
losses and require a higher ƒstep to achieve the same motor speed.
Table 10. Microstepping Indexer Settings
M1
M0
STEP MODE
0
0
Full step (2-phase excitation) with 71% current
0
1
1/16 step
1
0
1/2 step
1
1
1/4 step
0
Z
1/8 step
1
Z
Non-circular 1/2 step
Example: Target 120 rpm at 1/8 microstep mode. The motor is 1.8°/step
120 rpm u 360q / rot
¦step VWHSV V
N+]
1.8q / step u 1/ 8 steps / microstep u 60 s / min
(4)
8.2.2.2 Current Regulation
In a stepper motor, the full-scale current (IFS) is the maximum current driven through either winding. This quantity
will depend on the RREF resistor and the TRQ setting. During stepping, IFS defines the current chopping
threshold (ITRIP) for the maximum current step.
ARREF (kA:) 30 (kA:) u TRQ%
IFS (A)
RREF (k:)
RREF (k:)
(5)
Note that IFS must also follow Equation 6 in order to avoid saturating the motor. VM is the motor supply voltage,
and RL is the motor winding resistance.
VM (V)
IFS (A)
RL (:) 2 u RDS(ON) (:)
(6)
8.2.2.3 Decay Modes
The DRV8884 supports three different decay modes: slow decay, slow/mixed and all mixed decay. The current
through the motor windings is regulated using an adjustable fixed-time-off scheme. This means that after any
drive phase, when a motor winding current has hit the current chopping threshold (ITRIP), the DRV8884 will place
the winding in one of the three decay modes for tOFF. After tOFF, a new drive phase starts.
The blanking time tBLANK defines the minimum drive time for the PWM current chopping. ITRIP is ignored during
tBLANK, so the winding current may overshoot the trip level.
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8.2.3 Application Curves
Figure 26. Microstepping Using Slow Decay on Increasing
and Decreasing Steps; Current Loses Regulation on
Falling Steps
Figure 27. Microstepping Using Slow Decay on Increasing
Steps and Mixed 30% Fast Decay on Decreasing Steps
Figure 28. Microstepping Using Mixed 30% Fast Decay on
Increasing and Decreasing Steps
Figure 29. Microstepping Using Mixed 60% Fast Decay on
Increasing and Decreasing Steps
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9 Power Supply Recommendations
The DRV8884 is designed to operate from an input voltage supply (VM) range between 8 and 35 V. A 0.01-µF
ceramic capacitor rated for VM must be placed at each VM pin as close to the DRV8884 as possible. In addition,
a bulk capacitor must be included on VM.
9.1 Bulk Capacitance
Having appropriate local bulk capacitance is an important factor in motor drive system design. It is generally
beneficial to have more bulk capacitance, while the disadvantages are increased cost and physical size.
The amount of local capacitance needed depends on a variety of factors, including:
• The highest current required by the motor system
• The power supply’s capacitance and ability to source current
• The amount of parasitic inductance between the power supply and motor system
• The acceptable voltage ripple
• The type of motor used (brushed DC, brushless DC, stepper)
• The motor braking method
The inductance between the power supply and motor drive system will limit the rate current can change from the
power supply. If the local bulk capacitance is too small, the system will respond to excessive current demands or
dumps from the motor with a change in voltage. When adequate bulk capacitance is used, the motor voltage
remains stable and high current can be quickly supplied.
The data sheet generally provides a recommended value, but system-level testing is required to determine the
appropriate sized bulk capacitor.
The voltage rating for bulk capacitors should be higher than the operating voltage, to provide margin for cases
when the motor transfers energy to the supply.
Power Supply
Parasitic Wire
Inductance
Motor Drive System
VM
+
±
+
Motor
Driver
GND
Local
Bulk Capacitor
IC Bypass
Capacitor
Figure 30. Example Setup of Motor Drive System With External Power Supply
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10 Layout
10.1 Layout Guidelines
The VM terminal should be bypassed to GND using a low-ESR ceramic bypass capacitor with a recommended
value of 0.01 µF rated for VM. This capacitor should be placed as close to the VM pin as possible with a thick
trace or ground plane connection to the device GND pin.
The VM pin must be bypassed to ground using a bulk capacitor rated for VM. This component may be an
electrolytic.
A low-ESR ceramic capacitor must be placed in between the CPL and CPH pins. TI recommends a value of
0.022 µF rated for VM. Place this component as close as possible to the pins.
A low-ESR ceramic capacitor must be placed in between the VM and VCP pins. TI recommends a value of 0.22
µF rated for 16 V. Place this component as close as possible to the pins.
Bypass AVDD and DVDD to ground with a ceramic capacitor rated 6.3 V. Place this bypassing capacitor as
close as possible to the pin.
10.2 Layout Example
+
CPL
DECAY
CPH
TRQ
VCP
M1
VM
M0
AOUT1
DIR
PGND
STEP
AOUT2
ENABLE
BOUT2
nSLEEP
PGND
RREF
BOUT1
nFAULT
VM
DVDD
GND
AVDD
0.47 µF
0.01 µF
0.47 µF
0.22 µF
0.022 µF
0.01 µF
Figure 31. Layout Recommendation
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11 Device and Documentation Support
11.1 Documentation Support
11.1.1 Related Documentation
• PowerPAD™ Thermally Enhanced Package, SLMA002
• PowerPAD™ Made Easy, SLMA004
• Current Recirculation and Decay Modes, SLVA321
• Calculating Motor Driver Power Dissipation, SLVA504
• Understanding Motor Driver Current Ratings, SLVA505
11.2 Community Resources
The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective
contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of
Use.
TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration
among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help
solve problems with fellow engineers.
Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and
contact information for technical support.
11.3 Trademarks
PowerPAD, E2E are trademarks of Texas Instruments.
All other trademarks are the property of their respective owners.
11.4 Electrostatic Discharge Caution
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
11.5 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
12 Mechanical, Packaging, and Orderable Information
The following pages include mechanical, packaging, and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.
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PACKAGE OPTION ADDENDUM
www.ti.com
29-Feb-2016
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
Lead/Ball Finish
MSL Peak Temp
(2)
(6)
(3)
Op Temp (°C)
Device Marking
(4/5)
DRV8884PWP
PREVIEW
HTSSOP
PWP
24
60
Green (RoHS
& no Sb/Br)
CU NIPDAU
Level-3-260C-168 HR
-40 to 125
DRV8884
DRV8884PWPR
PREVIEW
HTSSOP
PWP
24
2000
Green (RoHS
& no Sb/Br)
CU NIPDAU
Level-3-260C-168 HR
-40 to 125
DRV8884
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability
information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that
lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between
the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight
in homogeneous material)
(3)
MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
(4)
There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.
(5)
Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation
of the previous line and the two combined represent the entire Device Marking for that device.
(6)
Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish
value exceeds the maximum column width.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
Addendum-Page 1
Samples
PACKAGE OPTION ADDENDUM
www.ti.com
29-Feb-2016
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
Addendum-Page 2
PACKAGE MATERIALS INFORMATION
www.ti.com
11-Mar-2016
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device
DRV8884PWPR
Package Package Pins
Type Drawing
SPQ
HTSSOP
2000
PWP
24
Reel
Reel
A0
Diameter Width (mm)
(mm) W1 (mm)
330.0
16.4
Pack Materials-Page 1
6.95
B0
(mm)
K0
(mm)
P1
(mm)
8.3
1.6
8.0
W
Pin1
(mm) Quadrant
16.0
Q1
PACKAGE MATERIALS INFORMATION
www.ti.com
11-Mar-2016
*All dimensions are nominal
Device
Package Type
Package Drawing
Pins
SPQ
Length (mm)
Width (mm)
Height (mm)
DRV8884PWPR
HTSSOP
PWP
24
2000
367.0
367.0
38.0
Pack Materials-Page 2
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